Salvinorin, isolated from Salvia divinorum, has been shown by spectroscopic and X-ray-crystallographic methods to be a trans-neoclerodane diterpene of structure (1). Crystals of compound (1) are orthorhombic, space group P212121 with a= 6.368(2), b= 11.338(3), c= 30.710(6)Å, and Z= 4. The structure was refined by leastsquares to R 0.052 and R′ 0.056.